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Roadmap for an 802.11ac Deployment

This Wisconsin district had plenty of mobile devices; but the network just couldn't keep up with the ever-growing user demand. Could a new ac infrastructure be the answer?

05/08/14

When Tim Peltz took over directorship of Information Systems for the Racine Unified School District in Wisconsin five years ago, Racine had a multitude of computing devices with the typical district mix: some that were 15 years old, some that were brand new, and a whole bunch in between.

Racine spent $1.7 million putting in a 10 gigabit fiber optic ring among 32 schools as a long-term lease deal, more than three-quarters of which was paid for through E-rate funding. All the district needed was new computers to exploit the potential.

So Peltz spent six to eight months pulling meetings together to convince district leaders that if they could collaborate with each other and give up individual departmental control over computer purchases (and the budget dedicated to those), it would save them money in the long run and make their operations more efficient, their staff more productive, and students and teachers happier about their in-classroom computing experiences. They finally agreed, the funding was pulled together, and Peltz and his crew spent an entire summer replacing 10,000 computers.

"It was probably the biggest technology-positive shift ever in this district," he noted.

Except over time it turned out not to be enough.

The Infrastructure Bottleneck
The main problem came down to the fact that Racine's wireless network design used centralized controllers for managing all of the access points (APs). The traffic would come to the six controllers in the district data center and then go back out to the school where the communication originated. That approach created a huge bottleneck.

As Peltz explained, "It worked fine when we first put it in. There weren't many devices and the applications being used weren't as bandwidth-intensive. As we started seeing more devices connecting to the wireless network — projectors, Apple TV streaming, even our phone network — things weren't working. It would take 20 minutes to get an entire cart of laptops online and to Google.com."

The challenge to find computers and study spaces only grew as more and more high school and some middle school students took advantage of online courses. In addition to students taking classes from the Wisconsin eSchool Network, local sections of online courses were created — all of which put pressure on the infrastructure by consuming ever greater amounts of bandwidth. Along with the content teacher, a mentor teacher at the student's school would provide support and encouragement to virtual students to make sure they were staying on track. That program is "huge," he says. "We're doubling if not tripling enrollment every single year."

Schools would continually put in work orders to supplement the wireless network with additional APs. But Peltz knew that wasn't the right approach. "Yes, they'd get on the network quicker, but there would still be that bottleneck of coming back to the main data center, hitting the controllers." Controller utilization was consistently between 90 percent and 95 percent from 7 a.m. to 3:30 p.m. "every single day," he recalled.

So a year ago Peltz threw up his hands and, with the superintendent's approval, put the kibosh on new device acquisition. "We needed to stop ordering mobile devices until we got a plan for our in-building infrastructure that included our network switching and our wireless."

That device embargo is still in place until the last of three phases of an infrastructure refresh is completed, expected before school begins in fall 2014.

Here's how Peltz and his IT organization are approaching the work of upgrading their site to equipment designed for 802.11ac.

This Time Around, Design for Capacity
The previous wireless network was designed for convenience and coverage. It was never really meant to accommodate the 30 to 40 computers in a single classroom, all streaming high definition video, Peltz said.

So even before the newest WiFi standard, 802.11ac, was formally adopted by IEEE at the end of 2013, Peltz had done his research and was ready to jump on. The new WiFi setup — encompassing 802.11ac APs, switches and controllers — adheres to that newest standard. "I took a risk. But it was an educated one, and it paid back," he says.

The tricky part of capacity design is that the APs can't be placed "too close together." When that happens, explained Peltz, one of the APs will "turn down its strength" to allow the other to ramp up its antenna and wireless signals."

Go for Precision in the Site Survey
Buildings in the Racine district range from slightly old to really old. "Some of our buildings were constructed when Lincoln was in office," said Peltz. "I'm not exaggerating." And those variations in construction make a difference in how many APs are required and where they're placed.

Back in 2006 when the first wireless network was put in place at the district, IT went around with a laptop to see if it could find the WiFi. This time Racine took a more considered route. It licensed Fluke Networks' AirMagnet Survey, an application that assesses real-world data that can influence the effectiveness of the wireless network. That includes building blueprints, building age, type of flooring and ceiling, size of classrooms, height and location of lockers, number of devices expected in each space and other details. Then AirMagnet Survey develops a wireless LAN network design and produces a printout specifying where each AP needs to be placed.

So far, said Peltz, a third of the way through the schools, the layout has been "rock solid." And, no, that's not following a one AP-per-classroom approach. Each location is specced out to accommodate between 40 and 50 devices in every single classroom.

That's not to say, he added, that "we're not going to have to come back and supplement with additional access points here and there, as more devices are brought into the environment."

How To Pick the Order of Deployment
At Racine, the teaching and learning team — not IT — picked two middle schools as the starting point for the new network. Why those two? "They had a significant amount of mobile devices that weren't being fully utilized," said Peltz, and technology use is going to increase even more as they implement some new STEM initiatives.

But from there, the networks in the high schools are being redesigned. And the reaction has been "awesome," he reported. "The feedback I've received from staff and students is that it's like they're on the fastest Internet connection they've ever seen. These things are like night and day."

Think Big, Negotiate Hard
Racine's previous wireless network was built on Cisco gear. So is the new one. The original price tag for the project was specced out at about $4.8 million, according to Peltz. That included replacing both managed and unmanaged Cisco equipment with Cisco Catalyst 3850 series switch and Cisco 5508 series wireless controller at each location, the latter licensed for whatever count of Cisco Aironet 3700 series access points are installed in that school. That decision alone eliminated the hub-and-spoke bottleneck problem of the previous generation of WiFi that relied on all controllers being placed in the main data center.

For the first time Peltz pursued E-rate priority 2 funding for those schools that qualified in order to cover a big part of that price tag, but it wasn't approved. Peltz didn't give up. The district was already qualified for state contract pricing, 42 percent off list. But, as he noted, "list pricing with Cisco is extraordinarily high." So he worked with his reseller Core BTS, a national company, to reduce the initial bid.

The final price was closer to $3.7 million, about $1.1 million off the initial estimate. "Cisco went above and beyond helping us out and getting the best possible pricing for this project," Peltz declared.

Get Creative for Funding
Even with the entire project coming in nearly a quarter under the initial estimate, the cost of the infrastructure upgrade was considerable for the district, which has an annual budget of about $225 million. Peltz explained that the funding came as a one-time source from lower personnel costs.

"The No. 1 thing I see among my peers in this state [is that] everybody hangs onto their own budgets and doesn't want to give up anything," he observed. Racine has been able to move beyond the district silos to get "everybody at the table to have open and honest conversations about what is in their budgets that they'd be able to sacrifice or give up to accommodate these improvements."

The result, they anticipate, will be "improvements that are going to make things for staff, students — even our facilities — more efficient in the long run. The instructors are going to have less downtime and be able to do a heck of a lot more actual instruction."

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